US2348995A - Control device - Google Patents

Description

May 16, 1944.

CONTROL DEVI C E Filed Nov. 29, 1941 lill/l M. K. PARKHURST ET AL 2 Sheets-Sheet l May l, 1944.

M. K. PARKHuRs-l: Erm. 2,348,995

CONTROL DEVICE Filed Nov. 29, 1941 2 SheetsLSheet 2 ATTORNEYS Patented May 16, 1944 CONTROL-DEVICE Malcolm K. Parkburst, New York, and Lyndon W. Burch, Pelham, N. Y., asslgnors to The Wllcolator Company, Elizabeth, N. J., a corporation of Delaware Application November 29, 1941, Serial No. 420,994

' (ci. 20o-11s) 24 Claims.

This invention relates to control devices of the type having a switch, valve or other control element movable between two positions automatically by an actuator and also manually by a handle, or the like, independently of the ,actuator, andhas particular reference to a novel device rof this type which includes means under control of the handle and responsive to operation of the actuator for locking the control element in one position against movement by the actuator. The new device may be made in a compact form and' is positive in operation.

The invention may be used for various purposes' but may be employed to particular advantage in electrical circuits to prevent overload conditions. Accordingly, the invention will lbe described and illustrated in the form of an automatic circuit breaker, although it will be understood that the invention may -be used for other purposes and may take other forms as well.

One feature of the invention resides in the provision of a novel-circuit breaker which, when the current exceeds a predetermined value, is operated automatically by a thermo-responsive element to open a switch in the circuit and hold it open independently of the thermo-responsive element by means of a locking member, and in which the switch may be closed by manual means operatively connected to the locking member. In a circuit breaker made in accordance with the invention, the switch may be opened automatically' means for the locking member is movable to rev turn the locking member against the action of its spring to its inoperative position where it is again latched. Also, when the switch is closed, the manual means is movable to release the latch so that the locking member under the action of its spring opens the switch independently of the operation of the actuator and locks the switch in its open position. Thus, the manual means serves the dual function of openingthe switch independently of the actuator and closing the switch after it has been opened by the actuator or the manual means.

Still another feature of the invention resides in the provision of a novel circuit breaker in which the switch may be closed manually even when the actuator tends to open it due to an overload condition in the circuit. In one form of the invention, the locking member for the switch is mountby a thermo-responsive member forming part of the circuit, the member being preferably in the form of a bimetallic snap element, and the switch is also movable to its closed position by manual means which may Ibe connected to the locking member for the switch. The locking member is normally inoperative, but when the thermo-re sponsive element is heated suillciently to open the switch, due to a current overload, the locking member is released and holds the switch in its open position so that it cannot be closed by the thermoresponsive element. When the manual means is moved to close. the switch, it also returns the locking member to its inoperative position where it is held until the switch is againr actuated by the thermo-responsive element.

Another featureof the invention resides in the provision of a novel circuit breaker in which the switch may beopened independently of the operation of the actuator. In the preferredconstruction, the locking member for the switch is.

urged by a spring, or theflike, in a direction for opening the switchbutis normally held in anginoperative position by a latch which is released 5o" ed on a lever which is urged in a direction to open the switch but is normally held by the latch for the locking memberin a position to permit closing of the switch. Preferably, the manual means for the locking member is movable to exert a cam action on the lever and thereby cause the lever to,

close the switch against the action of the actuator when the latter tends to open the switch. Accordingly, with the new construction, the circuit breaker may be closed manually and held closed in the event that an emergency makes it necessary to energize the circuit even when an overload condition prevails.

'I'hese and other features of the invention may be better understood by reference to the accompanying drawings, in which Fig. 1 is a vertical sectional View of a circuit breaker made in accordance with the invention;

Figs. 2, 3 and 4 are sectional views on the lines 2--2, 3-3 and 4 4, respectively, in Fig. l;

Figs. 5, 6 and 7 are Views similar to Fig. `1 but with the casing of the circuit breaker removed, illustrating different positions of the device;

Fig. 8y is a vertical sectional view of part o1' a modied form of the circuit breaker;

Fig. 9 is a diagrammatic view of aV circuit by y which the circuit breaker may be employed to control a current in excess of the capacity-ot the circuit breaker, and

10 is a view similar: to 9 showing-va er, illustrated, comprises-a.:

lto the locking member.

and ends of the frame being open. 'nie bottom 2,s4s,eas l Y end of the lever, the arms being connected to` y of the frame is seated on an insulating base 2| y to which it is secured by terminal screws 2 2 and 23 extending through aligned openings in the [rame and base, the screws being insulated from the frame and having their heads disposed above the bottom. A nut 24 is threaded on the outer end oi' each screw to clamp it in position and hold the frame against the insulating base. Preferably, the frame and base are enclosed in a casing made up of two removable sections 25 an'd 23a iltted closely over the sides of the frame and the base.

The terminal screw 22 supports an actuator in the form of a bimetallic snap element 21, the snap element being secured to the screw in any suitable manner, as by means of a. reduced portion 22a on the head oi the screw extending through an opening near one end of the. snap element and riveted over the element so as to clamp it against the head of the screw. Preferably, the snap element is oi the form shown in an application of Lyndon W. Burch, Seria1 No. 325,979, iiled March 26, 1940, now Patent No. 2,299,562, issued October 20, 1942. More particularly, the snap element comprises a sheet of bimetal having a pair of slots 23 extending along the intermediate portion of the sheet and diverging slightly toward its free end. The slo'ts terminate a substantial distance from the free end of the sheet, and the metal between the outer ends oi' the slots and the adjacent corners Yis crimped or gathered, as shown at 29, to reduce the effective perimeter of the sheet and cause it to assume a dished shape. A

control element in the form oi contact 30 is secured to the lower face of the snap element near its free end and coacts with a iixed contact 3| on the top of terminal screw 23.

By means of the terminal screws 22 and 23, the circuit breaker is connected in the circuit so that the current passes through the terminal 22, along the sheet of bimetal and through the normally closed contacts 30--3I to the terminal 23. As long as the current does not exceed a predetermined value, the snap element remains in its normal position (Fig. 1) Where it holds the contacts 30-31 irmly in engagement to complete the circuit. Howeverl if the current exceeds the predetermined value, it heats the bimetal 21 sufiiciently to cause it to reverse its curvature with a snap action and open the contacts, as shown in Fig. 5. By `properly proportioning the dimensions of the bimetal and the spacing between the slots 28, the snap element may be made to operate at any desired current rating to open the contacts. It will be apparent that after the circuit is broken by operation of the snap element, the latter immediately commences to cool because there is no longer a flow of current through it, and, accordingly, the snap element acts to return to its initial position and reclose the contacts. V

The switch oi the circuit breaker is provided with control means comprising a locking member 33 adjacent the free end of the actuator 21. Preferably, the locking member is made of insulating material and has a slot for receiving an ear 21a on the free end oi the actuator, the slot being elongated vertically so that theactuator vmay move up and down a limited distance relative The locking member is secured to a cross piece at the free end of a generaily U-shaped lever comprising a pair of spaced arms 34 movable on'a pivot 3l extending between the side walls 2B of the frame' at the opposite gether ,rigidly by a stud 33 intermediate their ends. The lever 34 is urged clockwise on its pivot 33, as seen in Fig. l, by suitable means such as a spring 31 coiled around the pivot and held at one end by the frame and at the oppomte end by a lug 33 on the lever above its pivot. Because of the spring 31, the free end of lever 34 is normally urged upwardy and tends to raise`"the`lockin8 member 33 and thereby open switch 3l-3l.

Normally, the locking member 33 is held in an inoperative position against the action of spring 31 by latch means comprising a trigger 40 movable on a pivot 4i on the free end of lever 34. As shown, the pivot 4I is mounted between raised extensions 42 on the` free ends oi' the lever arms, whereby it is located a substantial distance above the pivot 35 of the lever. The trigger cooperates with a toggle comprising a toggle arm 43 pivotally mounted between the kver arms 34 intermediate their ends, and a second toggle member in the form of a yoke having two toggle arms integral with a shaft 46 mounted between the sides 2t of the frame, as will be described in greater detail presently. 'I'he upper end of the toggle arm 43 is disposed between the toggle arms 45, anda pin 41 is mounted at its ends in the arms and extends through an elongated slot 4l in the arm v43. The toggle arms 43 are rotatable with the 'I'he trigger 40 extends through the space between the toggle arms 45 and is disposed onone side of vthe lower toggle arm 43 above pin41.` In its lower edge, the trigger is provided with a notch 52 in which pin 41 is adapted to be engaged, the notch having an undercut portion 52a for a purpose to be described. 'I'he free end of the trigger is urged downwardly to hold the notch over the pin, as by means of a spring 53 coiledv around the trigger pivot 4 I. Thus, in the normal position of the parts, as shown in Fig. 1, the toggle 43-45 is set against the action of springs 31 and and is positively held in its set position by trigger 40 which, because of its notch I2, prevents the toggle pin 41 from moving laterally and thereby breaking the toggle.

As long as the toggle is held in its set position by trigger 4l, the pin 41 engages the lower end of slot 40 and holds the lever 34 -down against the action of its spring so that the locking member 33 remains in its lowermost position and permits the switch 30-3l to be closed by actuator 21. However, the toggle is adapted to be released by operation of the actuator, and to this end we provide on the trigger 4l an insulating member 54 directly above the free end of the actuator. Accordingly, when the actuator' is overheated due to an excessive current in tleeir:` cuit, it snaps upwardlyagainst thetriggerzmember B4 and raises the trigger on `itstpivot "4i to disengage the notch .52v from toggle. pin 41.` Thereupon, the toggle breaks" under the actionf a very low temperature. When the toggle is re- `the left withy Shaft 48;"

audace leased by trigger an. the toggle pm n rides ui wardly inslotilt' and'outwardly along the lower edge of the triggenand thehanllle 49fmovesfto When it is desired to close switch 30.-3|, vthe handle is moved to the right, as seen in Fig.5, lto reset'the toggle. During this movement of the handle, toggle pin` 41 rides down the slot 43- and at the same time moves inwardlynnder trigger 40 until it isf opposite the notch' 52, whereupon the triggerI spring 53 snaps the trigger `downllever 34 downwardly about its pivot 35 and thereby 'returns locking member 33 to its inoperative position so 'that -they actuatorl 21; due toits cooling, closes the switch.l If the overload condition in the circuit has been removed,` the toggle is held in its sei'l position by engagement of its pin 41 in the trigger notch 52, vwhereby the locking member 33 is maintained inoperative and the switch remains closed. However, if there is still an overload condition in the circuit, the actuator is immediately reheated-by the excessive current and snaps back to its raised position so as to elevate-the trigger and release the toggle, whereupon the switch is again locked in its open position as previously described.

It may be desirable in some instances to'provide for closing the circuit even when it is overloaded, as, for example, when it is necessary to energize the circuit-temporarily for an emergency. In our new circuit breaker, the switch may be held in its closed position manually by handle 45 regardless of the operation of the actuator 21. More particularly, when the handle 49 is moved to the right to reset the toggle'4 and lower the locking member, as previously described, Vfurther movement of the handle to the right causes toggle -pin 41 to move laterally into 4l-extend,;the outer endsI ofv the sha'ftgbeing disposed in enlarged openingswis inthe sides lof the kframe. :The shaft 4 6, is normally, urged to the -rightinthe lframe openings 59, as by means .of spring l31... With this construction,` .whenhandle A49 is moved to. lthe left as seen in Fig. 7, the toggle shaft 46 is swung .bodily tothe left in the openingsi about the pins-58 of the bell crank lever as a pivot, the toggle pin 41 beingheld by trigger 4ll against ylateral movement` but being movabledovmwardly against the action of spring 31 to accommodate. this movement of shaft 46. As the shaft 46 swings lto theeleft, bell crank lever 51 is moved counter-clockwise on its pivot 58 so that the cross piece 51a is raised against the extensionl 5B `of the trigger and moves the trigger upwardly so asto disengage its notch 52 from the toggle pin 41 and thereby release the toggle. "Ihe lever 34 is then snapped upwardly byV spring 31, as previously described, and the locking member 3311s raised so asto move the free end ofthe' actuator 21' upwardly and thereby open the switch. Thereafter, the switch is held in its open position until handle 49 is moved to the right to reset the toggle and the trigger.

l In the device shownin Figs. 1 to '1, inclusive, the switch is closed and held closed independently of the actuator by forcing the handle to the right beyond its normal position, as shown in Fig. 6, so that the toggle pin 41 exerts a lateral thrust on the side of notch 52`r which is transmitted to the trigger pivot 4i, resulting in a turning moment on the lever which moves it counter-clockwise to cause insulating member 54 to depress Contact 3G. In the modified form of the device shown in Fig. 8, the turning moment for moving the lever to close the switch forcibly is obtained the undercut portion 52a of the notch 52 and v exert a thrust to the left against trigger 40. Since the toggle pin is ldisposed a substantial distance above the pivot for lever 34, this thrust exerts a turning moment onthe lever and causes it to move 'counter-clockwise-on its pivot against the action of spring 31. As a result, the insulating member 54 is moved downwardly against the free end of the actuator and forces contact 30 down against contact 3l, as shown in Fig. 6, the switch being held closed as long as the handle is forced to they right as far as it will go. During this action, the trigger -is prevented from moving upwardly on the `pivot 4l by the lateral thrust to which it is subjected by toggle 'pin 41 and by engagement-of thev toggle pin in the undercut notch portion 52a.' When the handle is released, the spring 31 movs'lever 34' upwardly on its pivot toy return the partsv to their' normal positions vshown -in Fig; A1, and if the-current vrpassing through the actuator lis still too'great, the latter y comprises twoarms connected byl thecrosspiece and pivoted intermediate their ends on pins 58 secured to thesides 20 of the frame.y At their ends remote from the cross piece, the'arms of the belllv crankleverare provided with openings *'(6 in a difierentvmanner. As there shown, the circuit breaker is similar in all respectsto that shown in Fig. 1 except that the'l reduced ends of toggle shaft 46 are mounted in inclined slots 59a in the side walls 2B of the frame. With this construction, the switch may be closed against the force of the actuator by operating the handle 49 to reset the toggle, as shown in Fig.y l, and then pressingthe handle downwardly so .as to cause the shaft 46,to ride down the slot 59a. Since `the toggle pin 41 is at the lower end of slot 48 when the toggle is reset, this downward movement of shaft 46 depresses the lower arm 43 of the. toggle, with `the result that the free end of lever 34' is moved downwardly about pivotv 35 to engage the insulating member 54 with the actuator andA force contact 30 against contact 3l. When member 5ftl is forced downwardly against `the actuator, the trigger 40may be held against upward movement onits pivot 4l by engagement of toggleY pin 41 in th'eundercut notchk portion 52a. or this undercut portion may'fbe eliminated and the trigger allowed 'to'k move upwardly a Yslight amount limited by the toggle shaftv 46, so that member 54l is effective to depress contact 30.

'The new circuit breaker is of compact construction and for this reason'is admirably suited for use in the circuits of aircraft, and the like, cr for other uses in which'the space requirement is an `vir'n'portant item. The circuit breaker is rpositive in actionlan'd because of the latching trigger Mi, the switch is prevented frombpening v'accidentally' due'to shocks orvibrations which are vfrequently encountered in aircraft.l tanks, automobiles, and other vehicles. Also, afterv an overload condition occurs in the circuit, the locking mechanism holds the switch positively'in its through which reduced ends of the toggle shaft swtch and tripping the locking mechanism. The

chcuit breaker may be made in a number of diierentcurrent ratings depending on the resistance of the bimetallic actuator 21, and it may be used to replace the fuse and toggle switch combination now in general use in aircraft, the device being adapted to be mounted in the space rrcviousiy occupied by the usual-toggle switch.

For some purposes, it may be desirable to use the circuit breaker to control a circuit carrying a current rconsiderably in excess of the current rating ci the circuit breaker. We have shown in Fig. 9 one ferm of a system in which the circuit breaker is adapted tor such use. As there shown, the circuit is arranged to energize a translating device, such as a motor 6I, from a battery l2 or other source of electric power, the battery being connected to the motor through`wires i3 and 64. The wires are of sumcient size to carry a heavy current for energizing the motor, and the iiow of current through the motor is under control of a relay 65 having a pair oi contacts normally bridged by a switch member 66. The

switch is urged away from its contacts by a4 spring $1 but is normally held in engagement with the contacts by a solenoid 68.

One side of the solenoid is connected through a wire 10 to one terminal of the circuit breaker ci our invention. shown diagrammatically at 1I, the other terminal of the circuit breaker being connected by a wire 12 to the main circuit at one side of the battery. The other side oi the solenoid is connected by a wire 13 to the main circuit between the other side of the battery and the relay 65. A low resistance element 1l connected inthe main circuit between the battery and the relay is normally shunted by a bimetallic snap element 15 connected by a` wire 16 to one side of the resistance and normally engaging a contact 11 connected to the other side of the resistance and the wire 13. Ihe snap element 15 is preferably similar to the snap element 21 of the circuit breaker, and when it is heated sumciently by the passage of current through it, its free end disengages contact 'l1 and snaps into engagement with a contact 1l connected through a resistance 19 to the wire 10.

The value` of resistance 14 is such that a small portion oi' the main current passes through snap element 15 and contact 11, and 'when the current in the main circuit becomes too high, the snap element 15 is heated to the point where it moves away from contact 11 and engages contact 1B. As a result, the current flowing through the circuit breaker 1I increases since it is now connected to one side of the battery through parallel paths of relatively low resistance, one path including solenoid El and the other path including resistance 1! and snap element 15. The snap element in the circuit breaker 1I has va current rating such that this increase in the current flowing through it, which is limited to a safe value by resistance 1l, causes it to open, whereby the energizing circuit for solenoid 88 is opened and the switch ii is disengaged from its contact so as to break the main circuit.

When it is desired to reenergize the motor il. the circuit breaker 1i is closed by operation oi its handle is, as previously described, with the result. that the solenoid 60 is reenergized and operates the relay to close the main circuit. I! there is no longer an overload condition in the main circuit, the snap element 1l, which cools and reengages contact 11 as soon as the main circuit is broken, maintains its normal engagement with contact 11 so that the circuit breaker remains closed. If the overload condition still exists in the main circuit and it is necessary to energize the circuit temporarily due to an emergency, the circuit breaker is held manually in its closed position, as previously described. While the main circuit is thus energized, the :snap` element "engages contact 18 due to the heating of this element by the overload current, but the resistor I9 is of such size that suillcient current nows through the solenoid 60 to hold the relay in its closed position.

'I'he relay, resistors and snap element 15 may be included in a compact unit andmounted near the element-to be controlled, and, accordingly, when the system is to be used on aircraft or other vehicles, it is unnecessary to employ heavy wires in the control compartmentl and the circuit breaker 'Ii may be mounted on the instiu-l ment panel where it requires no more space than the usual low capacity circuit breaker.

The circuit shown in Fig. l0 is arranged to energize a reversible electric motor 8| having forward and reverse vileld windings 82 and I3, respectively, connected in parallel. The motor is adapted to be energized from a battery or other current source 84 connected by a wire B5 toone side of the motor armature. The eld windings 82 and 83, which are connected to the other side of the motor armature, have wires IB and 81, respectively, leading to a wire 88 connected to the other side of the battery. Relays 89 and 90 are disposed in series with the field windings 82 and 83, respectively, for controlling the energizing of these windings from the battery.

The relay 89 is operated by a solenoid 9| connected at one side to wire 88 and at the opposite side through a wire 92 to a contact 93 coacting with a double throw switch 94. The other contact 95 of switch 94 is connected by a wire 96 to one side of a solenoid 91 for operating the other relay 90, the other side of the solenoid being `connected to wire 88. A low resistance element l is connected in the main circuit in series with the battery and the ileld windings and is normally shunted by a bimetallic snap element 99 connected to one side of the resistance and normally engaging a contact IIIII connected to the other side of the resistance. The value of the resistor 98 is such that a small part of the main current passes through the snap element 99, and when an overload condition occurs, the snap element is heated so that it disengages contact |00 and snaps into engagement with a contact IDI connected through a wire 102 and a resistance |03 to one terminal of the circuit breaker 1i, the other terminal of the circuit breaker being connected to the armature of motor Ii.

In operation, the switch 94 may be moved into engagement with contact 93 to energize solenoid 9| and close' relay 89, so that the ileld winding 82 is energized to cause the motor to rotate in the forward direction. When it is desired to re` circuit'through the iieldwinding 82.4 YWhen an y overload condition occurs inthe Lmain circuitv in either position of switch 94, the snap element movesaway from contact .Hllinto engagement with contact IM As a.v result, the current 4 through the actuator 21 of circuit breaker Il increases and operates the actuator to lbreak the circuit through the solenoidy SL81 which is energized at the time, whereby the main circuit ls opened. l

kIt is to be understood that .the control devicey of our invention may take other forms than that illustrated and is not limited to use in ccntrolling a switch, as it could be .arranged to voperate a valve or other control element. Also, the

actuator 21 for the control element may vbe of a different type than that illustrated and may be made to respond to any desired condition.

We claim: .g

1. A rcontrol device comprising a control element, an actuator for moving the controlelement, a locking member responsive to operation of the actuator for locking the controlelement against movement by the actuator, manually operable means f or moving the locking member to an inoperative position in which the control element is movable by the actuator, andmeans operable by said manual means for moving the control element independently of the operation4 l of said actuator.

2. A control device comprising a control element, an actuator for moving the control element, a locking member responsive to operation of the actuator for locking the control element against movement by the actuator, manually operable means for moving the lockingmember to an inoperative position in which the control element is movable by the actuator, and means operable by said manual means for moving4 the ,control element selectively from oneposition to another independently of the operation of said actuator.

3. A control device comprising a .control element, an actuator for movingl thel control element, a locking member responsive to operation ofthe actuator for locking the control element against movement by the actuator, and manually controlled means connected to 4said member for actuating it to move the control element independently of the operation of the actuator.,

4. A control device comprising a control -ele- 1 ment, an actuator for 'the element, a lockin'gmember responsive to movementofv the control element bythe actuator'from one position to a secondy Dositionlor locking the"` vcontrol element against movement back `.to its rst position, manual means operatively .f connected Ito the locking member, means operable bythe `,manual means for moving the locking memberrto an-inoperative position to release thecontrol-.element, andfmeans Vcontrolled bythemanual means, for operating the locking member-to move the control element from its first position to said second position independently of the operationof the, actuator.

. 5. A control device comprising al control element,I anI actuator -i'orthe element, a locking member responsive to i movement of. the control `element` by the actuator from one-position to a second position for locking lthe, control element against movement backtoits first position, manmeans operatively connected to the'locking member, and means voperable by said manual means for moving the control element back to its viirat position independently offthe operation 'of` ual meansoperatively connected to the lockingmember, means operable by said manual means for moving the locking member to release the `control element and for moving the control element back to its rst position independently of the operation of the actuator, and'means controlled by said manual means for operating the locking member to move the control element from its ilrst'position to said second position lindependently of the operation of the actuator.

7. A control device comprising a switch, an actuator for opening and closing the switch, control means for the switch including a locking member responsive to opening of the 'switch by the actuator'y for locking the switch against closing, and manual. means connected to the control means and operable to move the control means to one position for releasing the switch from the locking member and to a second position for open ing the switch independently of the operation oi the actuator.

8. A' control device comprising a switch, an actuator for opening and closing the switch, 'control means for the switch including a locking member responsive to opening ci the switch by the actuator for locking the switch against closing, and manual means connected to the control means and operable to move the control means to one position for releasing the switch from the locking member and vto a second position for closing the switch independently of the operation of the actuator.

9. A control device comprising a switch, an actuator for opening and closing the switch, control meansfor the switch including a locking member responsive to opening of the switch by the actuator for locking the switch against closing, and manual means connected to the control means land operable to move the control means to one position for releasing the switch from the locking member, to a second position for closing the switch independently of the operation of the actuator, and to a third position for opening the switch independently of the operation of the actuator.

y 10. A control device comprising a control element, an actuator for the control element, a lockv ing memberoperable to lock the' control element in one position against movement by the actuator, atoggle connected to they locking member and normally holding the locking member in an inoperative positionin which the control element is movable by the actuator, means responsive to operation ofthe actuator for movingA the toggle in one direction to release the locking member, and manual means for moving the toggle in the opposite direction to` secure the locking member tion, latch means normally set to hold the locking member in its inoperative position. means re- A sponsive to operation oi the actuator for releasing said latch means, and a manually operable device for moving the locking member to its inoperative position and setting the latch means.

12. In a control device having a movable control element, the wmbination of a locking member operable to lock the control element against movement and normally urged toward its locking position, a latch carried by the locking member for holding said member in an inoperative position, and means responsive to movement of the control element for releasing the latch to cause said member to lock the control element.

13. In a control device having a movable control element, the combination of a locking member operable to lock the control element against movement, a latch carried by the locking member for holding said member in an inoperative position, means responsive to movement of the control element for releasing the latch, and means responsive to release oi' the latch for moving the locking member to an operative position to lock the control element.

14. In a control device having a movable control element, the combination of manual means for actuating the control element, automatic means for actuating said element, a, locking member operable to lock the control element in one position, a latch coacting with said manual meansfor holding the locking member in an inoperative position, means kresponsive to movement oi the control element by said automatic means for releasing the latch| and means responsive to release of the latch for moving the locking member to an operative position tn lock the control element.

15. In a control device having a movable cony trol element, the combination o! a locking member operable to lock the control element against movement and movable between operative and inoperative positions, manually operable means V connected to said member for moving it to its inoperative position, a latch carried by the locking member for coacting with said manual means to hold the locking member in its inoperative position, means responsive to movement oi the control element for releasing the latch, and means responsive to release of the latch for moving the locking member to an operative position to lock the control element.

16. In a control device having a movable control element, the combination of a locking member for the control element, a pivot on which the locking member is movable between operative and inoperative positions, means for urging i, the locking member toward its operative position, a latch pivoted on the locking member for holding the member in its'inoperative position,

and means responsive to operation of the con-l trol element for moving the latch on its pivot to release the locking member and cause it to vlock the control element.

17. In a control device having a movable control element. the combination of a locking member for the control element, a pivot on which the locking member is movable between operative and inoperative positions, means for urging the locking member toward its operative position, a toggle connected to the locking member for moving the member to its inoperative position, a latch pivoted on the locking member and coacting with the toggle to hold the locking member in its inoperative position, and means responsive `connected to the locking member. means normally acting to expand the toggle and move the locking member to its operative position. a latch lcoacting with the toggle t0 hold it intl. Bet D081- tion against the action of said means and thereby maintain the locking member inoperative, and means responsive to movement o! the control element for actuating the latch to release the toggle and cause said member to lock the control element.'

19. In a control device having a movable control element and a locking member for the control element movable between operative and inoperative positions, the combination of a toggle connected to thelocking member, means normally acting to lexpand the toggle and move the locking member to its operative position, a latch movable on the locking member and coacting with part ofthe toggle for holding it in a set position to maintain the locking member inoperative, the latch having a part operable by actuation of the control element for moving the latch to release the toggle and cause said member to lock the control element. a handle connected to the toggle for setting it, the handle being operable to move the toggle beyond its set position against the action of said expanding means to exert a thrust on said latch part for positively holding the control element in one position, and a member operable by the handle for moving the latch to release the toggle.

20. In a control device having a movable control element and a locking member for the control element movable between operative and inoperative positions, the combination of a toggle connected to the locking member, means normally acting to expand the toggle and move the locking member to its operative position, a latch movable on the locking member and coacting with part oi' the toggle i'or holding it in a set position to maintain the locking member inoperative, the latch having a part operable by actuation of the control element for mowing the latch to release the toggle and cause said member to lock the control element, a handle connected to the toggle for setting it, and a member operable by the handle for moving the latch to release the toggle.

2l. In a control device having a movable con-` trol element and a locking member for the control eiement movable between operative and inoperative positions, the combination of a toggle connected to the locking member. means normally acting to expand the toggle and move the locking member to its operative position, a latch movable on the locking member and coacting with part of the toggle for holding itin a set position to maintain the locking member inoperative, the latch having apart operable 'by actuation of the control element for moving the latch to release the toggle and cause saidv member to lock the control element, and a handle connected to the tOggle for setting it, the handle being operable to move the toggle beyond its set position' against the action oi' said expanding means to exert a thrust on said latch part for positively holding the control element in one position. i

22. In a control device having a movable control element, the combination of a member operable to lock the control element against movement and normally urged toward its locking position, manual means for moving the locking member to an inoperative position and including an operating shaft which is rotatable and movable laterally, a latch for holding the locking member in its inoperative position and movable on actuation of the control element to release the locking member, a lever connected to the shaft, a pivot spaced from the shaft and on which the lever is movable, and a handle for rotating the shaft to actuate the manual means and operable to move the shaft laterally to fulcrum 1the lever on its pivot and thereby move the latch to release the locking member.

23. A control device comprising a switch, an actuator operable to open the switch and acting to close the switch on opening thereof, a normally inoperative member movable to an operative position for opening the switch independently of said actuator and for locking the switch open, a pivot for the locking member, a latch pivoted on the free end of the locking member, a toggle connected to the locking member and having an operating shaft which is rotatable and movable laterally, biasing means acting t expand the toggle and move the locking member to its operative position, the latch normally holding the toggle in a set position against the action of the biasing means and being movable by the actuator to release the toggle, a lever connected to the toggle shaft and pivoted independently of the shaft, and a handle for rotating the shaft to set the toggle and move the locking member to its inoperative position, the handle being operable to move the shaft laterally to fulcrum the lever on its pivot and thereby move the latch to release the toggle.

24. A circuit breaker comprising a normally closed switch, a bimetallic actuator for operating the switch, means for connecting the actuatory and the switch in series in the circuit Whereby excessive current heats the actuator and causes it to iflex and open the switch, a lever engageable at its free end portion with the actuatar, a pivot on which the lever is movable 'to cause the actuator to open the switch and hold it open, .a toggle connected to the lever for moving it to an inoperative position to permit closing of the switch by the actuator, the toggle including a toggle arm connected rigidly to the lever, an operating shaft, a toggle arm on the shaft, and a pin on one of the arms disposed in a slot in the otherarm, biasing means acting to break the toggle and move the lever to lock the switch in its open position, a' latch pivoted on the free end portion of the lever and. having a notch engageable with the pin to hold the toggle in a set portion in which the lever is inoperative, the actu.- ator being movable relative to the lever to fulcrum the latch on its pivot and thereby disengage the notch from the pin, means for urging the latch toward the pin, a latch releasing member connected to the toggle shaft and pivoted at a point remote from the shaft, and a handle for rotating the shaft to set the toggle and operable to move the toggle beyond its set position against the action of said biasing means to cause the pin to exert a turning moment on the lever through the latch and thereby move the latch bodily to close the-switch against the action of the actuator, the handle being operable to move the shaft bodily to fulcrum said member on its pivot and release the latch independently of the actuator.

MALCOLM K. PARKHURST. LYNDON W. BURCH.

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